Destructive hydrogenation of hydrocarbon oils with molybdenum oxide catalyst



Feb. 12, 1952 OILS WITH MOLYBDENUM OXIDE CATALYST Filed Feb. l5, 1949 GATALYST summer AREA (M2/G) N C0 O m. m, m.

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PERCENT M0 o3 IN SILICABLUMINA BASE YRCENT M0 O5 IN SILlCPS-"HLUMINB BASE CHIYLYST 5 2 SHEETS-SHEET 1 CONVERSlON OF STOCK TO GASOLINE, @pas fx COKE; (Qa) Y fifi. Q. A P

PERGENT Mo Oa 1N SILIG-ALUMINA BASE 2 I5 4 5 6 7 E E) 12 CHTBLYSTS @ERG/ENT M0 O3 IN Simca@A ALUMINA BASE Gg-BTALYSTS s Q 0 O. N N l H O YDROSf-N CONSUMPTION (flo OF STOCJSN n IN1 'ENI 0R. JOSEPH B. MCKINLEY ATTORNEY J. B. MCKINLEY DESTRUCTIVE HYDROGENATION OF HYDROCARBON Feb. l2, 1952 OILS WITH MOLYBDENUM OXIDE CATALYST 2 SHEETS-SHEET 2 Filed Feb. l5, 1949 GAS a CGK/E (m) O CONVERSION OF STOCK TO GASOLINE,

hmmm @5201@ 655 5 mo o2 aummm W #l CATALYST SURFA mais LN2/G) O o t0 ATTORNEY Patented Feb. lz, 1952 DESTBUCTIVE BYDROGENA'TION 0F HY- DBOCABBON ,OILS WITH MDLYBDENUM XIDE CATALY ST Joseph B. McKinley, Pittsburgh, Pa., assigner to Gulf Research Development Company, Pittsburgh, Pa., a corporation o! Delaware Application February 15. 1949, Serial No. 76,629

Claims. (Cl. 19H9) This invention relates to an improved procedure for converting hydrocarbon oils into lighter products, and more particularly to the hydrocracking or destructive hydrogenation o! low grade petroleum stocks such as recycle gas oils from thermal or catalytic cracking in the presence of a molybdenum trioxlde-cracklng base catalyst.

It is known to subject hydrocarbon oils such as low grade petroleum stocks to hydrocracking or destructive hydrogenation under conditions which eil'ect hydrogenation as well as cracking in order to convert the hydrocarbon oil into gasoline or lighter products. Among the catalysts which have been used in the past for promoting these reactions is molybdenum trioxide supported on a silica-alumina or other cracking catalyst base or carrier. A method commonly employed in the past in preparing this type oi catalyst involves impregnating the base with an aqueous solution of ammonium paramolybdate to which has been added an excess of the amount or just the theoretical amount of ammonia necessary to convert the paramolybdate to the normal ammonium molybdate. The impregnated base is then dried and calcined in air to obtain the iinished molybdenum trloxide-cracking base catalyst.

This invention has for its object to provide a destructive hydrogenation or hydrocracking procedure whereby the yield of gasoline can be materially increased. Another object is to provide an improved destructive hydrogenation or hydrocracking procedure yielding a high quality gasoline product. A further object is to provide an improved destructive hydrogenation or hydrocracking process which employs a low molybdenum content catalyst which is more active in this process than prior art catalysts. A still turther object is to provide an economical procedure tor converting relatively heavy hydrocarbon oils into light products and especially into gasoline. Still another object is to provide an improved process for the destructive hydrogenation of petroleum stocks which employs a catalyst having high activity which is prepared in such a manner as to be particularly adapted for use in destructive hydrogenation processes. Other objects will appear hereinafter.

These and other objects are accomplished by the present invention which includes hydrocracking or destructive hydrogenation o! a hydrocarbon oil by contacting it with hydrogen under 2 base with a solution prepared by dissolving molybdenum pentachloride in water followed by drying and calcining.

The active cracking component of the catalyst which will be referred to as the cracking base, is preferably a synthetic or natural cracking catalyst of the well known silica-alumina type. The synthetic catalysts are preferably prepared by coprecipitation. However, other well known active cracking catalysts may be used as the cracking component. Thus. the cracking component may be any one which is known in the art to be active for catalytic cracking. as for example, a silica-zirconia, silica-titania, silica-alumina-titanla, or silica-alumina-boric oxide. cracking catalyst.

To prepare the composited catalyst which is to be employed ln my process, a cracking catalyst. as for example silica-alumina. is impregnated with a solution prepared by dissolving between about 0.1 and molybdenum pentachloride in water. The exact nature of the hydrolysis products o! molybdenum pentachloride in the solution is not known. However, it is known that es during subsequent drying and calcining in air conditions giving rise to hydrogenation and V cracking while in the presence of an active cracking catalyst composited with molybdenum trioxide, M003, or as commonly called, molybdena. said molybdena having been deposited on the active cracking catalyst base by impregnating said the molybdenum in solution is converted quantitatively to molybdenum trioxide or molybdena on the catalyst. The ireshly prepared catalyst may also contain small amounts of other oxides than molybdena. During use of such a catalyst in destructive hydrogenation the molybdena is at least partially reduced. The impregnation may be eiected by soaking the cracking catalyst base with the solution. Vacuum impregnation. which involves contacting the impregnating solution with an evacuated cracking base. gives a more thorough distribution of the solution through the cracking base and is the preferred method of impregnation. The length of time for soaking the evacuated base may be from 5 to 30 minutes. and the preferable temperature is in the range of 15 to C. After impregnation the catalyst is dried in conventional manner for instance at a temperature in the range oi 212 to 260 F. for l0 to hours, and then calclned by heating in air at elevated temperature such as about 900 F. The concentration ot the molybdenum in the solution prepared irom molybdenum pentachloride may be varied so as to produce a molybdena-silicaalumlna catalyst containing varying amounts of molybdenum trioxide. It is known in the prior art that the percent of molybdenum trioxide in a molybdena-cracking base catalyst can vary to a large degree and this is true in accordance with my invention. However. I have iound that my invention is of unusual value in connection with catalysts which have between 0.5 and 6.0% molybdenum trioxide and preferably between 0.5

water. The samples were nrst evacuated and.

then contacted with said solutions in a closed system. Each sample was impregnated with a solution ot a dierent concentration varying from 0.72% to 14.93% molydenum. calculated as xnolybdenum trioxide, in order to deposit varying amounts of molybdenum trioxide on the catalyst samples. The five impregnated samples were ovendriedandthenealcinedinairtoconvert the impregnant to the oxide. The speciiie temperatures and lengths of time for dryingr and calcining and other details of preparation for etch of the lmmtod catalysts are given in the following table.

TABLI I Concentration of 0m l l the Mol bdmum mi Cnam Catalyst No. Containlvnl Solumi. Pdf t?" T2?" uw Per Oni 0. 1I 1I N. 5 Il) 0vernlght l. 4I 1I 70 D Do. I. 18 103 I). 5 il!) Do. 7.10 |02 n 5 900 Do. ll. l 102 Il. s 900 Do.

IOven i All loihln heat-up period.

times be referred to as molybdenum pentaehloride solution.

vapors of the hydrocarbon stock and hydrogen are contacted with a catalyst prepared as described above at temperature and pressure usual to destructive hydrogenation procedures. The pressure should be superatmospheric. for example, from about 1000 to 5000 p. s. i. or higher, the temperature should be from about 750 to 900 1".. and from about 5 to 30% hydrogen by weight as compared with the charge stock should be employed. Suitable hydrocarbon stocks for sub- Jecting to destructive hydrogenation are thermal- 1.7 cracked. catalyticalLv cracked. or virgin hydrocarbon oils. and especially highly aromatic cycle stocks from catalytic cracking. Reduced crudes. pressure still tars, and similar materials also may be treated, preferably in admlxture with lowboiling material so that they are substantially in tbe vapor phase during ordinary conditions for destructive hydrosenation. Stocks which are substantially in the liquid phase under normal destructive hydrogenation conditions tend to be soaked up by the catalyst. This condition favors cracking rather than destructive hydrogenation for hydrogen absorption by the catalyst surface is hindered and thus it is not favorable for obtaining best results with my preferred catalysts.

In its preferred embodiment my invention involves the use of 0.5 to 4.0% molybdenum trioxide deposited on the cracking carrier. This range gives greatest activity as demonstrated by the data in Example I wherein catalysts prepared by the molybdenum pentachloride impregnation method and varying in molybdena content from 0% to 11.7% were tested.

lmmple L Pive samples of co-precipitaied silica-alumina catalysts of uniform quality and ll'ecalclnod in air at 1000 1". were tested for their destructive hydrogenation activity with varying amounts of molybdenum trioxide deposited thereon. All were impregnated with solutions pre- In bot ovm.

gstarted ustartedmooldhirnaosandmleinhigtimeincludcssitohmu The above catalysts and an unimpregnated base (also precalcinedl" were tested for destructive hydrogenation activity with a. light cycle stock from a Thermoi'or catalytic cracking operation by a standard procedure in a two liter rocking bomb. The tests were on an equal weight basis. In each test the bomb was charged with 13.6 grams of catalyst, 8.5 grams of hydrogen, and 175.0 grams oi' cycle stock. The bomb, containing catalyst, hydrogen and cycle stock. was heated in 132 minutes to a temperature of 835 l". That reaction temperature was maintained for 47 minutes with an average maximum reaction pressure of 2100 p. s. i. g. The bomb was then cooled in an air blast for 60 minutes to reduce the temperature to 300 F.. at which time the bomb was water quenched.

The characteristics of the cycle oil, which was the charge stock in these tests, is given in Table II below.

TABLE 1I Inspection of light cycle oil No. 1, from a Tirer-molar catalytic cracking Operation Bp. El. at 60760 F 0.8849

Table III gives the results of the tests for the five molybdena-silica-alumina catalysts and the pared hy dinolvins molybdenum pentachloride in Unlmxircsnated silica-alumina base.

ascuas? V TABLE m Meer of molybdeno content mi me activity of molilbdena-silica alumina catalysts Unirnpregnated Catalyst Nnmbu Billes-Alumina Il I2 Il n Wt. Pucsnt M00. (i) 0. b 1.0 1 7 6. 6 11.7 Surface Area mfg 317. 7 280. 3 UB. 4 30.2 223.4 Products (lt. Fel-cant o! Charge Stock):

4.1 0. 2 10.0 0.8 6.6 6. 6 toawl? 18.104.111 37.2615) 404007) 43.li3a4) 81.5616) 60.105,0 Li uldlosidmsbovoo'l" 76.8 62.6 48.3- 40.6 63.3 03.0 Co L4 1.0 0.7 0.6 0.4 0.3

Total a 0 100. 0 100. 0 100. 0 100. 0 100. 0 100. 0 Conversion oi Stock to Gualino Gas and Coke (Wt. Pcomt o! Charge Stock)I i9. 6 42. 7 47. 0 48. 8 42. 0 32. 3 Hydrogen Consumption (Wt. Percent of C Stock) 0. 42 l. 16 1.82 2. i3 l. 08 1. 6b Ratio oi to n-Butme in Gascon:

Products 0.7:1 1.5:1 1.4:1 1.2:1 i.l:l 0.7:1 Properties oi Products- Gasoline:

Sp. Gr. at 60"/00" F 0.779 0. 768 0. 768 0. 188 0. 768 0. 774 Br.No l3.l 4.2 2.6 1.3 0.0 27 Raidue:

Sp. Gr. at 60"/00" F 0. 9013 0. 8736 0.8623 0. 8544 0.8002

l Charge stock i None.

i Conversions are csllculatod as weight percent oi material boiling above 400 F. in the charge minus weight percent ol'similnrly boiling liquid materials in the produ The figures in parentheses are the conectad gasoline yields; the actual observed weight percent yield minus the weight percent gasoline in the charge stock.

The curves presented in Figures l to 4 inclusive oi the drawings were obtained by plotting the Table III test results for specic gravity of residue (Fig. l), hydrogen consumption (Fig. 2). catalytic surface area (Fig. 3). and conversion oi stock to gasoline. gas, and coke (Fig. 4). against the six values for percentages oi molybdenum trioxide in the catalyst samples. The six points plotted in each graph were connected by a smooth curve.

The curve oi Figure 1 indicates that an optimum specific gravity of residue can be obtained with a catalyst of about 2% molybdenum oxide in the molybdenum trioxide-cracking base catalyst. 'I'he low value for specific gravity oi' residue is considered optimum since it most probably represents a lower molecular weight and/or more saturated residue and hence is a material of better quality than higher specific gravity residues for charge to subsequent destructive hydrogenation treatments or cracking operations.

The curve of Figure 2 indicates that hydrogen consumption will be highest for a catalyst containing about 2% or slightly more molybdenum trloxide. Large hydrogen consumption is of course an indication oi high catalytic activity.

The curve of Figure 3 indicates that catalytic surface area decreases as the molybdena. content increases.

The curve ot Figure 4 indicates that a maximum conversion of stock to gasoline. gas and coke will be eilected by a catalyst having a molybdena content of about 2.0%.

Molybdenum trioxide-cracking base catalysts prepared by the molybdenum pentachloride lmpregnation method show the greatest superiority over the catalysts prepared by prior art methods in the molybdena. content range oi from about 0.5 to 6% molybdena and especially in the low molybdena content range oi from about 0.5 to 4.0% molybdena. Since practically all molybdenacracking base catalysts are most active or reach maximum activity when they contain 0.5 to 4.0% molybdena. the molybdenum pentachloride lmpregnation method is most elective when impregnating the preferred amount of molybdena on cracking catalysts.

I have conducted tests `to demonstrate the superiority of the destructive hydrogenation process of this invention which employs a catalyst prepared by molybdenum pentachloride impregnation method over the prior art process which employs a catalyst prepared by the ammoniacal ammonium paramolybdate method of impregnation. Example II gives the details of tests using low molybdena. content catalysts (i. e., 0.5-1% molybdena) prepared by the two diilerent methods.

Example [1 -Six samples o! silica-alumina cracking catalysts of uniform characteristics and precalcined at 1000 F. were selected. Three oi' these samples I shall designate as A. B. and C. I contacted the samples A. B. and C. after evacuatlng, with aqueous solutions o! molybdenum pentachloride having concentrations ot 0.56%, 0.97% and 1.38%. respectively of molybdenum calculated as MoOa. Each of these samples was oven dried at a temperature and for the length of time indicated in Table IV. Following the drying period the catalyst samples were calcined in air at about 900 F. for about 16 hours in a muiile furnace to quantitatively convert all impregnant on the cracking catalyst base into molybdenum trloxide. The three remaining cracking catalyst samples which I designate as D. E. and F were prepared in an identical fashion except that the impregnation was performed with an aqueous solution of ammonium paramolybdate. (NH0eMo1Oz4AHzO, to which had been added the theoretical amount of ammonia necessary to convert the paramolybdate to the normal molybdate. (NI-m2191004. Table IV gives the details of preparation of the six catalysts A, B. C, D. E, and F.

While conditions under which catalysts may be prepared by the molybdenum pentachloride impregnation method can vary widely without much effect upon the iinal catalyst activity. care was taken in this and the following example to make conditions of all preparations. regardless of method. as nearly identical as possible in order that the superiority to be shown for the molybdenum pentachloride impregnation method Each of the six catalysts before testing was reduced in a 6000 STP space velocity hydrogen stream at 000 k1". overnight. cooled to room temperature and contacted with oil and hydrogen. in such a manner as to prevent reoxidation before and during testing. For testing each of the six catalysts, a two liter rocking bomb was charged with 23 cc. of the reduced catalyst. 8.5 grams oi' hydrogen. and 175.0 grams oi' cycle should be unambiguous. l stock. The bomb. containing catalyst. hydrogen,

TABLE IV Impregnsting Solution Oven Drying l Calcining l Catalyst Molybdenum Typs Employed Oonoetrtlon T939" T" Tilp" Timo Per cent 0. 56 |25 2l 9m overnight i 0. 97 126 2l 900 D0. 1.38 123 2l 900 D0. A.P.M.+NH||.. 0.56 l2! m0 D0. A.P.M.+NH1-- 0.08 126 19 000 D0. A.P.M.+NH|-- 1.40 1% l0 000 D0.

l See footnote i, Table I. 2 See footnote 2. Table I l Ammonium parnmolybdate (A.P.M.) solution plus enough added ammonia to form the normal The six catalysts A. B. C. D, E, and F. were then subjected to comparative destructive hydrogenation tests under conditions similar to those set i'orth in Example I. The charge stock was a Thermofor catalytic cracking cycle oil having the following characteristics.

and cycle stock, was heated in 125 minutes to a temperature of 790 F.. maintained at 700 P. for minutes, and then cooled in an air blast 30 for 60 minutes to reduce the temperature to 300 F. at which time the bomb was water quenched. Table VI gives the results of these tests.

TABLE VI Comparzson of actimty of low molybdena content catalysts made by dierent impregnation methods Catalyst A B C D E p Prepared by Impregnating Cracking Base with (l) (I) (1) (a) Per cent M00; 0. 4 0. 7 1. 0 0. 4 0,1 1, Surface Area. mlg 289. 5 28D. 5 m. e m, 4 277, 4 2r.; Products (Wt. Per Cent oi Cycle Stock): (3)

C4 and Lighter 4. 4 5. 7 s. 1 a. s 5. 4 5,5 Gasoline to 400 F 3. 4 26.4(2341) 32. 5(29. 1) 36. nasa) 24.7(21 3) 29. ze o) 31 4(2941) Residue above 400 F. 00. 6 68. 7 61.3 50. 7 7l.0 64. 7 6l. 6 Coke (Approx.) 0.5 0.5 o. 5 o. s u, s 0, 5

Total 100.0 100- 0 i00. 0 100. o 100. o 10o. o 109,0 Conversion of Stock to Gasoline, (las and Coke (Wt. Per Cent of Cycle Stock) 27.9 35.3 39. 9 25, 31, o 3.5 0 Hydrogen Consumption (Wt. Per Cent of Cycle Stock) 1. I3 l, 60 l. e6 1, oo 1, 4s 1 52 Properties of Products- Gasoline:

Ep. Gr. at /00 F 0. 188 0. 760 o. 764 0. 77s a 'm o. 16s Br. No 0. 9 0.4 o. 2 1.1 n.1 o. 4 Residue:

Sp. Gr. at 60l60 F 0. 8565 0. B476 i)` 844s 0.8613 o. 351s o. 3413 l M. P. C Molybdenum Pentachloride Solution.

I A. P. M.Ammonium Psramolybdate in Ammoniacal Solution.

l Charge. See footnote 4, Table III. See footnote 3, Table IIL TABLE V Inspection of light cycle oil No. 2, from a Thermofor catalytic cracking operation The data oi' Table VI are plotted in Figures 5 to 8 inclusive where it is readily seen that catalysts in the low molybdena content range are most suitable for destructive hydrogenation where they have been prepared by the molybdenum pentachloride impregnation method. The dotted line curves represent the values obtained for the catalysts prepared by the prior art method of ammoniacal ammonium paramolybdate impregnation and the solid line curves represent the values obtained for the catalysts prepared by the molybdenum pentachloride impregnation method.

Thus. Figure 5 shows that destructive hydrogenation, using a catalyst prepared by the molybdenum pentachloride impregnation method, results in a lower specific gravity oi the residue than in the process employing a catalyst pre- 0 pared by the ammoniacal ammonium paramolybdate impregnation method.

Figure 6 shows that hydrogen consumption is greater when the catalyst prepared by the molybdenum pentachloride impregnation method is employed.

Figure 'I shows that the surface area of the catalyst prepared by the molybdenum pentachloride impregnation method is greater.

In Figure 8 it is seen that the destructive hydrogenation process of this invention employing a catalyst prepared by the molybdenum pentachloride impregnation method has the important result of converting more stock to gasoline, gas. and coke and particularly to gasoline and gas since coke formation is small, than the prior art method employing the catalyst prepared by the ammoniacal ammonium paramolybdate impregnation.

I have made additional tests to determine the advantages of destructive hydrogenation with catalysts prepared by the molybdenum pental0 II were selected ior preparation o! tive molybdena-cracklng base catalysts which I designate as G. H, I. J. and K. Three of these samples were impregnated with aqueous solutions of molybdenum pentachloride. dried. and calcined in the manner explained in Example II to form catalysts G. H, and I. In these preparations however. the concentration of the impregnating solutions were such as to prepare samples containing 1%, 3%. and 6% by weight of molybdenum trioxide, respectively. The two remaining cracking catalyst samples were impregnated with ammoniacal ammonium paramolybdate solution. dried, and calcined as in Example II to form catalysts J and K. The impregnating solutions were more concentrated than those in Example II so that catalysts containingfhigher percentages of molybdenum trioxide, namely 3% and 6% by weight were obtained. The speciiic details of preparation of the five catalysts ot this example are listed in Table VII.

TABLEVII Impregnsting Solution Catalyst Type Employed Molybdenum Concentration l I- l Bee footnotes to Table IV.

chloride impregnation method having a relatively high molybdena content as explained in Example III.

Example IIL-Five silica-alumina cracking These five catalysts were subjected to destructive hydrogenation tests under conditions identical with those of Example II and employing portions of the same cycle stock that was charged catalyst samples having a higher surface area 45 in the Example II tests. The results ot the tests than the cracking catalyst samples in Example are given in Table VIII.

TABLE VIII Comparison of activity of high molybdena content catalysts made by dierent impregnation methods Catalyst G H I J K Pre ared by Impregnating Cracking Base with (I) 1) 1) e) m Percent M00:

r 7. l 7. 4 B. 7 1. 5 1. 8 Gasoline to400 F. 3.4 41.968, 5) 40,967.6) 30.9(33J5) AMCD 'JMD Residue above 400 F. 96.6 50. 5 51. 2 53.9 57.0 51.0 Coke (Approx.) 0. 5 0. 5 0. 5 0. 0 0. 5

Total 1w. 0 100. 0 100. 0 100. 0 1&0 1N. 0 Conversion of Stock to Gasoline. (las and Coke (Wt. Percent of C cie Stoek)l 4G. l 45. 4 42.7 44.0 44.1 Hydrogen Consumption t. Percent of Cycle Stock 1.97 LW 1.99 L 1.96

parties of reductaasoline:

Sp. Gr. at 0l60 F 0. 762 0. T60 0. 706 0.758 0.759 1'. No 0.5 0.3 0.2 0.2 0.6

ue: 8p. Gr. at 60"!00" F 0. 8303 0. 8378 0` 8303 0.8m 0. M08

l See footnote to Table VI.

i See footnote to Table VI.

l Charge.

Ses footnote 4 to Table m. 'SeelootnotetoTshlsIlL The Example III results indicate that even for these higher moiybdena content catalysts. the catalysts prepared by the molybdenum pentachloride impregnation method i'or each ot the tested percentage compositions gives superior results for specific gravity of the residue. hydrogen consumption, and surface area. Also the conversion of stock to gasoline, gas. and coke is greater for the molybdenumlpentachloride prepared catalysts throughout much o! the composition range tested. y

What 1 claim is:

1. The process oi destructively hydrogenating a hydrocarbon oil which comprises contacting said oil with hydrogen at an elevated temperature and superatmospheric pressure in the presence of a catalyst which is prepared by impregnating a silica-alumina cracking catalyst base with an aqueous solution of molybdenum pentachloride and drying and calcining the resulting mass to convert the impregnant into molybdenum trioxide, said molybdenum pentachloride being deposited in an amount sutilcient to result in a calcined catalyst containing between about 0.5 and about 4% molybdenum trioxide. said molybdenum trioxide being deposited in an amount suillcient to result in a calcined catalyst containing between about .05 to about 4% molybdenum trioxide.

2. A process for destructive hydrogenation of a hydrocarbon oil which comprises contacting the vapors o1' such oil with hydrogen at an elevated temperature and superatmospheric pressure while in the presence of a catalyst which is prepared by compositing a silica-alumina cracking catalyst base with between about 0.5 and 4% by weight molybdenum trioxide said compositing being effected by impregnating said base with an aqueous solution of molybdenum pentachloride and drying and calcining the impregnated base to form molybdenum trioxide on said base.

3. The process oi destructive hydrogenation which comprises contacting the vapors of a heavy hydrocarbon oil with hydrogen at a temperature above about 750 F. and a pressure above about 1000 p. s. i. while in the presence of a catalyst which is obtained by impregnating a silicaalumina base with an aqueous solution of molybdenum pentachloride and drying and calcining to form molybdenum trioxide on the silicaalumina. base, the amount and concentration of said solution o! molybdenum pentachloride being sumcient to form between about 0.5 and 4% molybdenum trioxide on said base.

4. The process which comprises subjecting the vapors of a heavy hydrocarbon oil to a temperature oi between about 750 F. and 900 F. and a pressure of between about 1000 and 5000 p. s. i. while in the presence of hydrogen and a catalyst which is obtained by impregnating a silicaalumina base with an aqueous solution of molybdenum pentachloride and drying and calcining the impregnated base to convert the impregnant into molybdenum trioxide. the amount and concentration of said solution being suillicent to form between about 0.5 and 4% by weight molybdenum trioxide on said base.

5. The process of destructive hydrogenation which comprises subjecting the vapors of a highly aromatic cycle stock from a catalytic cracking operation to a temperature of between about '750 F. and 900 F. and a pressure of between about 1000 and 5000 p. s. i. while in the presence of hydrogen and a catalyst which is obtained by impregnating a silica-alumina base with an aqueous solution of molybdenum pentachloride and drying and calcining the impregnated base to convert the impregnant into molybdenum trioxide, the amount and concentration of said solution being suiiicient to form between about 0.5 and 4% by weight molybdenum trioxide on said base.

JOSEPH B. MCKINLEY.

REFERENCES CITED The following references are of record in the ille oi' this patent:

UNITED STATES PATENTS Number Name Date 2,271,617 Benedict Feb. 3, 1942 2,341,792 Kanhoier Feb. 15, 1944 2,377,728 Thomas June 5, i945 2,500,197 Michael et al. Mar. 14, i950 

1. THE PROCESS OF DESTRUCTIVELY HYDROGENATING A HYDROCARBON OIL WHICH COMPRISES CONTACTING SAID OIL WITH HYDROGEN AT AN ELEVATED TEMPERATURE AND SUPERATMOSPHERIC PRESSURE IN THE PRESENCE OF A CATALYST WHICH IS PREPARED BY IMPREGNATING A SILICA-ALUMINA CRACKING CATALYST BASE WITH AN AQUEOUS SOLUTION OF MOLYBDENUM PENTACHLORIDE AND DRYING AND CALCINING THE RESULTING MASS TO CONVERT THE IMPREGNANT INTO MOLYBDENUM TRIOXIDE, SAID MOLYBDENUM PENTACHLORIDE BEING DEPOSITED IN AN AMOUNT SUFFICIENT TO RESULT IN A CALCINED CATALYST CONTAINING BETWEEN ABOUT 0.5 AND ABOUT 4% MOLYBDENUM TRIOXIDE, SAID MOLYBDENUM TRIOXIDE BEING DEPOSITED IN AN AMOUNT SUFFICIENT TO RESULT IN A CALCINED CATALYST CONTAINING BETWEEN ABOUT .05 TO ABOUT 4% MOLYDBENUM TRIOXIDE. 